On Apr 23, 6:56*pm, RJO wrote:
I've had a great Sony SW7600 portable shortwave/AM/FM radio for years
and it has worked very well. It's probably been on for more than ten
thousand hours overall. This is the model:

http://www.universal-radio.com/catal...icfsw7600.html

A few months ago it started giving only loud static when turned on,
even when tuned to a standard station. If I left it on for an hour or
two it would usually snap back to normal operation and the station
would come in clear again. But now it's gotten to the point that it
never comes back: only loud static when turned on, and for all the
time it is left on. You can faintly detect the signal in the
background in most cases, but it's drowned out by the static. (These
are strong stations I've listened to for a long time; something
changed in the radio, not the environment.)

My mechanical intuition tells me the problem is simple, but I know
nothing about electronics. Is anyone familiar with these old workhorse
portables? If the repair is more complex than whacking it with a
hammer I probably couldn't do it myself, but perhaps it would be worth
sending it out for repair? Or should I toss it in the wastebasket?
Sell it for parts on eBay?

Many thanks.

Bob

From your description, it could be a failure of the solder. Sony has
been notorious for solder problems depending on the factory and
product as well as era it was made. If you can open the set and
operate it, then you could gently probe the components with a thin
insulated probe to see if a bit of pressure in an area restores
operation. One problem doing this is that if the defective joint is
actually moved, it can restore operation for hours, days or months
before it re-appears, If prodding does restore operation, then it is
often effective to simply resolder every joint that looks even
slightly suspect with a suitable small iron and top quality rosin
solder. If the radio is not RoHS compliant, then use tin-lead 63-37
solder.
If prodding around has no effect, the problem might be a defective
semi-conductor. You might also consider replacing all the electrolytic
caps since they are prone to going high ESR with age, again depending
on the date and make.

Neil S.